As someone who uses both platforms for work and personal entertainment, I've been wanting to do a performance comparison between Windows 7 and Mac OS X since I first got my hands on the Windows 7 RTM (the final build of the OS) more than two months ago, but decided to wait until I could compare the two apples to apples. (No pun intended.)
The right time seems to be now, as Snow Leopard has been out for a while and has even been updated to 10.6.1, and Windows 7 has been at the OEM (original equipment manufacturer) vendors for almost three months and has also had a few updates. Furthermore, Boot Camp 3.0 seemed to make Windows run better than ever on a Mac.